Retaining Walls in Shoreline, WA

Frequently yes, and on these streets it usually looks better than replacing it with block. Rockeries fail progressively rather than suddenly — stones work loose, the face bulges where soil has washed out through the gaps, and the toe spreads — which means a single failing section can often be reset without disturbing the rest of the run. The limit is a rockery that has moved along its whole length, where the interlock that held it has gone and patching buys a couple of years at best. We look at the whole run before quoting a section of it.

The slope is sensitive both to what you put on it and to where water goes, so a wall there is a structural question rather than a landscaping one. Bluff-edge ground along the Sound carries looser material than the plateau behind it, and adding load above a slope or routing surface water over its edge is exactly the mechanism that turns stable ground into moving ground across several wet seasons. On these lots we look at where water leaves the property before looking at what goes on it, and we would rather say a wall belongs somewhere else than build it in the wrong place.

The community's long-standing covenants address preservation of views between properties, which means height on this street is not purely your own decision in the way it is elsewhere in Shoreline. In practice that is worth establishing before design rather than after — a terracing scheme that solves your level problem and creates a covenant problem for a neighbour helps nobody. It cuts both ways, too: the same rules that constrain what you build protect your outlook from what somebody above you might. We check what applies to your property at the outset.

Because the ground here is the same glacial till that underlies north Seattle, and flat ground on till drains worse than sloped ground rather than better. Water reaching the hardpan stops, saturates the topsoil above it, and then has nowhere to run — so soil packed straight against the back of a wall on a level lot is saturated soil for a good part of the year, and saturated soil pushes. Perforated pipe at the footing, free-draining rock against the face and a real discharge point are not a hillside luxury here; they are what stops a low garden wall tipping.